Giant Nonreciprocal Band Structure Effect in a Multiferroic Material
Phys. Rev. Lett. 135, 206401 – Published 14 November, 2025
DOI: https://doi.org/10.1103/15ws-ftbf
Abstract
Multiferroic materials, combining ferroelectricity and ferromagnetism, can host complex band phenomena. Using density functional theory and symmetry analysis, we identify the multiferroic EuO as a prototypical system exhibiting a giant, switchable nonreciprocal band structure effect, that is an asymmetry in electronic bands at special points in the Brillouin zone, enabled by spin-orbit coupling. In particular, our results highlight the crucial role of magnetic symmetries—beyond inversion and time-reversal breaking. Ultimately, the predicted effect leads to a colossal bulk photovoltaic response, with injection currents far exceeding those in known oxides, enabling new cross-functionalities.
